Limit control



Oct. 30, 1945 H. F. PARKER 2,338,219

LIMIT CONTROL Filed Sept. 1, 1943 I lgnnnnmumumm muuk illy/Ill,

I INVENTOR 2/ Ff- HUMPHREY F PARKER ATTORNEY:

Patented Oct. 30, 1945 UNITED STATES PATENT ,OFFICEI Humphrey F. Parker, Kenmore, N. Y., assignor to. Q

Columbus McKinnon ChainCorporation, Tona- Wanda, N. Y., a corporation of New York,

Application September 1, 1043, Serial No. 500,804 .1

6Claims. (o1. 192- 1ss) My invention relates in general to controls for limiting the upward movement of a movable abutment, and in particular, to controls for use upon electrically operated hoists of the type wherein a weight is slideably mounted upon the cable and suspended from a spring actuated switch arm. In devices of this type, when the hoist block has reached the upper end of its predetermined travel, the block will engage the weight, causing the same to be lifted, thus counteracting the spring and allowing it to actuate the switches to first interrupt the current supplied to the motor for hoisting and then to check any upward drift of the block by reversing the current to the motor.

In order to facilitate the assembling of the weight about the hoist cable, it is preferableto make it in two parts, which are secured together by means of bolts. It is well known, however, that difficulty is experienced by the workman in holding the parts in registration and at the same time placing the fastening bolts in position. i

The principal object of myinvention hasbeen to provide'a multi-part weight, the parts of which are permanently connected together and suspended from ring means, whereby theywill be held in registering positions so as to enable the workman to conveniently assemble the bolts therewith. i i

Another object has been to-provide weights having apertures so proportioned in relation to the suspending means, that the parts of the weight will be held in operative relation with each other upon the cable in the absence of fastening bolts due to the camming action between the suspending means and the weight parts.

Moreover, the parts of my invention are so designed that in order to separate the weight parts to assemble the same about the cable, the suspending means must be moved to a position at an angle to the suspending position where it wil act as a hinge for the weight parts.

Another object has been to provide a switch arm in the form of a bell crank lever with novel spring pressed means for actuating the same.

The above objects and advantages have been accomplished by the device shown in panying drawing of which:

Fig. 1 is a fragmentary view of an electric hoist showing my invention applied thereto;

Fig. 2 is an enlarged fragmentary sectional e1ethe accom-' vation of the weight arm and the spring means thereof;

Fig. 3 is a side elevation of the weight showing the suspending ring;

7 formed at the top on oppositesidesfwith a Fig, 4 is a fragmentary inside view of one of the weight parts; and, r Fig. 5 is a plan view showing the weight sec separated for assembly'upona cable. As shown in the drawing, lllrepresentsan'elec trically-driven hoist having a casing H and a'r'l end wall l2. The hoist is provided with the usual cable drum l3 upon which the cable If! is passed. The hoist block isrep resented at H. The dead end 16 of the cable is passed over a stud 20" and ananchor 2| formed at this end; of the cable 'en gages] a lug 22 andserv'es' to hold this end of "the cablein place. o I The weight 23 of my invention is engagedwith the pass 24 extending downwardly from the dead end It and is 'slideable thereon a's will herein after be more fullydes c'ribed, The weight co n prises two parts'25'and 26; each formed witha; longitudinal recess 30; forjslidefable engage'm e b with the cable. 7 The weight 'is .of 'general pei shaped configuratiomjand eachjof the parts; is ess 3| thereby providing parallelIateralfianges QZ'. Each of these flanges is provided with an :a.perture 3 3 for the passage of the suspendingmeans Which'is preferably in the form of a closed ring 34, whereby the parts are ,permanentlyjiastened together in, a relatively loosemanner 'Ihelsize of the apertures 33 and the diameter of thelwire formingthe ring 34 is such that when theweight parts 25 and 26 aresuspended from the .ring,.a cammingactionwill be produced upon the flanges which will hold the flanges and the integral body parts closely together and in engagement with the cablewithout useof any fastening means, The ring and weightsare suspended from a chain 35 and the camming action just described will be effective so long as the ring remains in aplane substantially parallel to "the aXis ofthe cable engaged by the weight, and solong asthe'sus pending chain isheldtaut. The parts ofwthe weight are, however, preferably secured together by means of bolts 36 which pass'through an aperture 40 formed in one of the sections andintqla threaded aperture 4| formed in the opposite section. A recess 42 is preferably provided one section for the reception of the head of thebolt thereby disposing the bolt" head within the general contour of the weight.

As shown in Fig. 5, the parts 25 and 26' may be separated for assembly upon the cable and this the ring will act as a hinge for the weight parts.

The weight lever 43 of my invention is mounted upon a shaft 44 journaled in a housing 45. This housing is preferably secured to the end wall I2 of the hoist. The lever is formed with an arm 46 which is engageable with a spring plunger 50 slideablymounted within a cylindrical housing projection This plunger is preferably formed with a, centrally arranged aperture 52 in which is disposed a compression spring 53. One end of the spring bears against the head 54 of the plunger and the other end against a spring screw 55 which is screwthreaded into the housing part 5|. The spring 53 is of sufficient strength to cause the weight arm to be rotated when the weight 23 is elevated. The lever housing 45, as shown in Fig, 1, is secured to the end wall 12 of the hoist housing and the lever 43 is extended to a position near the weight 23 through a suitable aperture formed in the wall. "The suspension chain '35 which engages the suspension ring 34 is provided at its upper end with an eye bolt 56 which is screwthreaded into the outer end 60 of the lever 43 from which it is normally suspended.

The-shaft 44 carrying the weight arm also carries switch operating cams BI and 62 which control switch arms 63 and 64, respectively. The switch arms 63 and 64 are connectedto suitable switches 65, only one of which isshown in Fig. 2. The arm 63 is connected to the switch which controls the load lifting circuit of thehoist, and its actuation through the medium of the cam 6| will interrupt the current to the motor, thereby causing the hoist to stop. In the event that the hoist continues its operation, under momentum of-the switch arm 64 will be brought into engagement with the recess =66 of the arm 62-and thereby energize the motor to cause its reverse rotation.

.In the operation of myinvention, it will be obvious that the weight parts will be constantly suspended from the suspension ring and suspension chain due to gravity exerted by the weight 23 during the upward travel of the hoist block to its upper predetermined limit, thereby obviating any slackness in the chain. When, however, the weight is elevated by contact with the upwardly moving hoist block l5 as it approaches the upper limit of its predetermined travel, the counteracting effect of the weight upon the spring 53 will be relieved and the spring will cause the weight arm 43 to be moved upwardly and thereby obviate any slackness in the suspension chain. This, due to the cam locking action of the ring 34 upon the flanges '32, will maintain the suspension ring in substantially the position shown in Fig. 3, thereby preventing the weight parts from separating should, the fastening bolts 36 for any reason be missing. Itis obvious -that when-the counteracting influence of the weight 23 is removedfrom the weight lever. the lever as above described will be moved upwardly as described through the medium of the spring and will cause the switches 65 to be actuated in the manner described.

Having 'thus described my invention, what I claim is:

A suspended control member for a hoist,

' locking action will be relieved. In such position comprising a weighted body having complemental sections for loosely embracing the load-suspending cable of the hoist, each section having a cablereceiving groove and a fastener-receiving aperture, and means operatively suspending the weighted body and including a ring loosely engageable wtih both sections thereof, said suspending means being such that when supporting the sections the fastener-receiving apertures thereof will register with each other for receiving a. fastener.

, 2. A suspended control member for a hoist, comprising a weighted body having body sections for loosely embracing the load-suspending cable of the hoist, and a vertically arranged suspending yring member loosely connecting the sections oi after the hoisting current is interrupted, the roller the body and adapted to hold them in cable-ems bracing position when in body-suspending posi-, tion.

3. A suspended control member for a hoist, comprising a weighted body having complemental sections for loosely embracing the load-suspending cable of the hoist, and flexible means suspending the weighted body, said suspending means including an oscillating ring member supporting the sections, said ring member being adapted to lie in a vertical plane when in its body-suspending position to hold said sections in cable-embracing position, said ring member beingosciilatable to a substantially horizontal position for releasing the sections, whereby the latter may be separated for placement upon or displacement from said cable.

4. A suspended control member for a hoist, comprising a weighted body having complemental sections for loosely embracing the loadsuspending cable of the hoist, each section having a cable-receiving groove, each of said sections having a .coacting flange formed with a registering aperture, and means operatively suspending the weighted body and including a ring loosely engageable with the apertures .of the section flanges, said ring being adapted to hold said sections in cable-embracing position when said sections are suspended therefrom.

5. A suspended control member for a hoist, comprising a weighted body having complemental sections for loosely embracing the'load-suspending cable of the hoist, each section having a cable-receiving groove, cam locking means carried by said sections and connected to a support, said cam means being adapted to be moved in response to changing forces transmitted through said support to provide relative movement of said body sections, and means carried by said sections for locking the same in cable-embracing position.

6. A control member ior a hoist comprising a body of plural sections for slidably embracing the load-carrying element of the hoist, means for locking said body sections in element-embracing relation, and means i or supporting said body sections including cam locking means interconnecting said body sections and a suspension member therefor, said cam means being arranged tobias said sections into element-embracing relation upon tensioning of said suspension member.

F. PARKER; 

